Re: [Qemu-devel] [PATCH] i386/kvm: expose HV_CPUID_ENLIGHTMENT_INFO.EAX and HV_CPUID_NESTED_FEATURES.EAX as feature words

[Eduardo Habkost]

On Mon, Dec 03, 2018 at 03:17:06PM +0100, Vitaly Kuznetsov wrote:
> Eduardo Habkost <address@hidden> writes:
[...]
> > But note that we might still be able to move the existing
> > "hyperv_*" features to feature_word_info[].feat_names.  We just
> > need to keep the same semantics (e.g. enable
> > HV_HYPERCALL_AVAILABLE automatically when some features are set).
> >
> > Maybe we can make some of the feature properties read-only.  This
> > way we can give them meaningful names for debugging and error
> > messages, even if we don't want to make them configurable
> > directly.
> 
> I'd suggest (if there are no objections of course) we do this separately
> from this patch. [...]

Agreed.

>            [...] Some time ago when merging direct mode stimers for KVM
> Paolo suggested we stop adding capabilities to KVM for each individulat
> feature and replace them with something like KVM_GET_SUPPORTED_HV_CPUID
> ioctl returning all Hyper-V related feature words. When this is done we
> can reconsider how Qemu discoveres Hyper-V related KVM features and as
> part of this work we can take a closer look at feature words and
> feat_names.

Why a separate ioctl instead of extending GET_SUPPORTED_CPUID?

-- 
Eduardo